1. Field of the Invention
This invention relates generally to the field of vehicle travel surface condition monitoring and control systems, and more particularly to a vehicle mounted and/or stationary positioned system for determining characteristics of surface materials related to adverse driving conditions which includes a vehicular mounted weather monitoring subsystem for measuring weather conditions at the vehicle location.
2. Description of the Related Art
Stationary weather stations have weather vanes and wind velocity meters to provide wind direction and speed information (velocity), and sensors to provide relative humidity, air temperature, and precipitation amounts and rates, among other parameters, to local and remote locations. Some aircraft also have been equipped with similar equipment to monitor conditions in thunderstorms and hurricanes. However, such instrumentation has commercially not been installed on motor vehicles.
Road condition service vehicles such as snow plow trucks and surface conditioning vehicles which deposit materials such as sand and chemicals such as salt to travel surfaces depending on the current or predicted road surface conditions do not carry weather analysis equipment on board. Proper surface conditioning materials are optimally applied during the early stages of adverse weather conditions as well as throughout the adverse weather condition. However, the optimal distribution of materials and compositions change dramatically as the storm progresses through a locality. Currently there is no real time weather sensing apparatus available that can be vehicle mounted which determines weather conditions such as wind speed and direction, temperature, humidity, precipitation events, water content and rates of deposition, and barometric pressure.
A number of attempts have been made to sense the conditions of roadways, aircraft runways, and other surfaces for vehicular traffic, during changing adverse weather conditions For example, it is known to place conductivity, temperature and other sensors either in the road surface or adjacent the road to monitor the temperature of the road surface, the subsurface temperature and/or monitor whether there is ice forming on the surface. Atmospheric sensors may also be provided adjacent the road. This information can then be fed to a central location for control and dispatch of trucks to apply salt or sand or other deicing mixtures. At airports these types of warning systems are used to inform maintenance crews that the runways need to be treated or alert the staff that deicing procedures need to be implemented. Some conventional systems have a supply of chemicals and pumps beside the roadway or runway to automatically spray the road when triggered by a sensor.
There is also a need for such a warning system on road vehicles such as cars, buses and trucks to detect pending adverse conditions. However, available mobile systems are limited to basic moisture detection and temperature monitoring systems. Some examples of such systems are disclosed in U.S. Pat. Nos. 4,492,952 and 4,678,056. One particular system, disclosed in U.S. Pat. No. 5,416,476, employs an infrared sensor which is mounted on the exterior of the vehicle and sends a signal to a microprocessor which then can display the temperature of the road surface. These systems are simplistic and do not tell the operator the critical information needed under all conditions, such as, what is the composition of and at what temperature will the particular material actually on the road surface freeze? Therefore there is a need for an on board material sensing apparatus and system for determining when an actual liquid on a road surface will freeze in view of current weather conditions at the vehicle location and alerting the operator to such adverse driving situations before they actually occur so that the operator can adjust material spreading techniques and strategies accordingly.
There is also a need for a mobile mounted sensing apparatus and system for use by road crews to evaluate current local weather conditions and determine and evaluate existing materials, if any, on a road surface in order to determine the optimumal amount, type and timing of additional material to be applied to the surface in order to reduce the current and future hazardous driving conditions.
There is also a need for an apparatus and system for predicting, displaying and sometimes controlling the distribution of travel surface conditioning materials available on board local road crew trucks based on current and predicted local weather conditions at the travel surface location. Such a system is unavailable today.
The system in accordance with the present invention addresses the above described needs. It is thus an object of the present invention to provide a unique multipurpose system which includes a vehicle mounted surface monitoring portion and/or a weather condition monitoring portion. In addition, the system preferably includes a fixed or mobile system for receiving and/or measuring weather conditions at vehicle locations and predicting and forecasting future travel surface conditions to provide recommendations for and verification of surface conditioning activities and results.
The surface monitoring portion may include a multipurpose sensor mounting platform accommodating a variety of sensors that enables the temporary use of materials such as surface water and road conditioning materials actually encountered on a road surface to determine the condition of the road surface. It is another object of the invention to provide a system for remotely detecting the actual materials and/or characteristics of materials on a roadway and determining a characteristic such as friction coefficients, chemical composition or the actual freezing temperature of a material on a road surface regardless of the makeup of the material or depth of the material.
It is a still further object of the present invention to provide a reliable display of information to the vehicle operator of actual and pending conditions of the road surface. It is a still further object of the invention to provide an apparatus for sensing actual road conditions that can function automatically or manually and which permits automatic or manual control of distribution of on board conditioning materials.
It is a still further object of the present invention to provide a system for remote sensing and evaluation of material present on a roadway surface which includes a means for extracting sufficient information to determine the characteristics of the composition of the surface material and utilizing user input information as well as local weather conditions at the vehicle location, as well as at fixed locations, to calculate the amount of additional material, if any, and what type, to be applied to the road surface to mitigate the development of future adverse conditions. This may involve utilization of look up tables, of historical data for the location, continual updating of such tables with actual data from the location, and utilization of algorithms for predicting future conditions at the site.
Throughout this specification, the term xe2x80x9cvehiclexe2x80x9d is meant inclusively to refer to any moving vehicle, whether it be a land vehicle such as a salt truck or an airborne or orbital vehicle such as an airplane or satellite. The sensing portion of the system of the present invention may be adapted for mounting and operation on any such vehicle. The vehicle referred to with respect to carrying and distributing surface conditioning materials typically is a truck.
One embodiment of the apparatus for sensing surface material condition in accordance with the present invention comprises a collection means for receiving material discharged, for example, from a vehicle wheel in contact with a roadway surface, at least one sensing means coupled to the collection means for detecting a characteristic of the received material such as friction coefficients, temperature, conductivity, and chemical concentrations and producing a corresponding signal, processing means for converting the corresponding signal, and display means connected to the processing means for providing an indication of surface conditions based on the material characteristics.
The collection means may include a modified mud flap located immediately behind a vehicle wheel so that a portion of any surface material that is picked up by the vehicle wheel and thrown toward the flap may be collected. An alternative collection means is a scoop located in proximity of the wheel or adjacent the road surface to collect deposited surface material. Another alternative is a separate sensor wheel contacting the vehicle travel surface which has sensors mounted thereon or therein for analyzing the deposited surface materials.
Another embodiment of the surface monitoring portion of the invention does not require a collection means, but instead, remotely senses directly the surface material characteristics such as temperature, conductivity, friction coefficients or chemical concentrations. This embodiment utilizes a sensor or series of sensors located on the undercarriage of the vehicle at a preferably fixed distance from the road surface which senses the surface temperature and at least one other unique surface material characteristic so that the specific material or materials can be identified, the composition determined, and freezing temperatures determined. This embodiment may also include a subsurface radar or other electromagnetic radiation transceiver directed at the ground for determining road surface temperature when the roadway is ice or snow covered and determining the temperature of the underlying ground beneath the vehicle travel surface.
Another embodiment of the apparatus has a sensor mud flap which includes a channel leading into a detection chamber where liquid runoff from the wheel flap is periodically collected and then frozen. The freeze point is sensed along with the temperature of the incoming material. The freeze point may be determined as the collected material changes from liquid to solid or as the material changes from solid to liquid during thawing of a sample. This freeze point information is displayed to the operator of the vehicle. Once the freeze point is determined, the frozen material is fully thawed and discharged from the chamber so that a new sample may be collected and analyzed.
Another embodiment of the surface material monitoring portion of the present invention includes an endless belt of liquid absorbing material mounted to the flap. The endless belt collects and absorbs liquid collected by the flap, transports it to a collector which extracts the liquid from the belt and directs it to the sensor means which also can be a detection chamber where the chamber contents is frozen in order to sense the freeze point.
The sensing means may be a single sensor or a combination of several sensors to detect particular parameters of interest. The road conditions are primarily affected by changes in temperature, wind, dew point, and material concentrations. Therefore the sensing means may include resistance temperature detectors, thermocouple, infrared temperature sensors, conductivity detectors, close proximity electromagnetic radiation (EMR) transmitters and detectors or transceivers, friction measurement devices, and other material analysis systems such as a spectrographic analysis system such as a mass spectrometer or laser induced breakdown spectrometer. In the latter case, the mass spectrometer or other material analysis device would preferably be mounted inside the vehicle, with a sample conveying means such as a belt or pump line directing the sample from the flap or other collection platform such as a scoop, etc. into the analysis device, eg., the vaporizing chamber for the spectrometer. Alternatively, an ultra wide band Doppler radar or any other suitable electromagnetic radiation (EMR) emission and detection technique as well as Laser Induced Breakdown Spectroscopy (LIBS) looking directly at the material on the road surface may be used to remotely ascertain chemical and physical characteristics of the material on the roadway surface. As another alternative, several of the above sensing devices could be directed toward materials still on the travel surface, on a moving belt, moving past the sensor, or flying through the air.
The processing means may include a microprocessor for converting sensed signals to display signals, store potential material data, determining material identity and pertinent material characteristics, and includes power and signal transmission means. This processing means can be located in several locations, including in the vehicle or remote from the vehicle.
The display means may be a panel with indicators of the freeze point, the ambient temperature, and other meteorological characteristics as well as surface material characteristics, and connections to more detailed signal analysis equipment such as chart recorders, tape recording devices, or other processing equipment. The display means may also include suggested remediation actions, alarms and inputs to automatic functions such as activating anti-lock brake systems, or transfers from two wheel to all-wheel drive systems, or activating chemical spreader control functions.